Temptation
by Nnoitra-Szayel
Summary: On his way to bed, Sirius discovers Regulus doing something unusual... WARNING: this fic contains BLACKCEST


_A/N: friendly reminder that just because I write it doesn't mean I ship it :)_

 _ **WARNING: THIS FIC CONTAINS BLACKCEST. IF REGULUS/SIRIUS IS NOT YOUR CUP OF TEA, YOU KNOW WHERE THE BACK BUTTON IS!**_

Temptation

Regulus didn't understand. Ever since they had came home for summer break, he'd started to find his older brother, Sirius, to be very alluring. When he went to bed at night, all he could think about was how he wanted to be touched by his older brother, and as he jerked himself to a completion every night, he would close his eyes and see the beautiful grey eyes of his brother staring into his own. At the end, he would moan Sirius' name as he came all over the sheets. He'd quickly fall silent to make sure no one had heard him. Once he was satisfied that the house was silent, he'd pull out his wand and clean himself up. He would lie on top of the sheets, trying to calm down but he was too hot, too aroused. Soon, he would find himself picturing Sirius naked, picturing Sirius naked and in the shower, even picturing Sirius wanting him. Then he'd clean himself up again and be able to fall asleep.

In the morning, he woke up to the sun streaming in through the murky windows. It didn't help that he'd dreamt about Sirius snogging a girl instead of him. Consequently, Regulus glared contemptuously at his brother from across the table. Sirius merely stared back with a bemused expression on his face, thinking that his younger brother had stumbled upon one of the fake rats he had put in the shower, completely unaware that his brother was tempted to kick him under the table.

Dinner that same night was silent; the only thing that could be heard was the gentle clanking of silverware against plates. Regulus stared at his brother the whole time, practically devouring him with his eyes; the smooth curve of his shoulders beneath the well fit black silk shirt, the days worth of stubble… Regulus could only imagine what it would be like to kiss him like that… to feel the rough texture of the skin beneath his smooth palm…

"Regulus. Quit daydreaming and eat your dinner," Orion Black said coldly.

"Yes, Father," Regulus said with difficulty as his hardening member gave a painful twitch at these new fantasies. From across the table, Sirius was letting a subtle smirk play across his lips, noticeable enough to Regulus, but nearly undetectable to Orion and Walburga.

Later that night, Regulus decided to turn in early so he could get to dreams of his brother sooner. Regulus closed his eyes and imagined Sirius walking into his room and climbing into his bed. He pictured his brother resting his hand on his thigh and then stroking down towards his knee. Then Sirius would climb on top of him with the sort of lazy elegance that only someone bred as carefully as him could possess. At first, Sirius would kiss Regulus gently, but then Regulus would press up into his brother, making it much more heated, much more urgent. Sirius would slide his hands under Regulus' shirt, thin fingers stroking pert nipples. A soft moan escaped Regulus' throat as he shivered in pleasure. Soon, his shirt was off and they were snogging intently while Sirius roughly thrust his hips down into Regulus', creating the sense of a friction that Regulus wished could be real. Erection throbbing painfully in the boy's tented pyjama pants, he fisted his hand in the sheets and moaned wantonly. "Sirius…"

Outside the door, the sound of a stack of books being dropped could be heard.

xxxx

After dinner, Sirius had decided that he would avoid everyone by going to try and get some of his summer homework done. Most of the time, however, he just used his parchment to write letters to his friends. By nine o'clock, Sirius had managed to complete his Defense Against the Dark Arts essay. Deciding that this was good enough for one night, he collected everything and headed back down to his room wondering why he always brought so much stuff with him.

As quietly as possible, he passed Regulus' door, which was open a crack. He had almost cleared his younger brother's room when Regulus' wanton voice moaned out "Sirius…." Shocked, Sirius dropped his books, the noise echoing dully throughout the hallway. Heart beat speeding up, Sirius moved so he could see into Regulus' room. Regulus was lying in the middle of his bed, sheets pushed down to the foot of it, his trousers rested mid-thigh, and his hand was wrapped tightly around his swollen cock, quickly stroking up and down. Sirius let out a breathy gasp. Why was this so… pleasing?

Sirius stood there watching his brother get off, strangely engrossed. No girl had ever had him this interested… but then again, no girl had ever been his brother. This was so wrong. And yet, he could feel himself wanting to go in. He wanted to be the one who made Regulus come. He wanted to be the one eliciting such wonderful noises from his brother. He felt himself twitch as Regulus moaned his name again. Sirius managed to tear himself away from the door to go to and look down the stairs, trying to discern if his parents were actually paying attention to what their children were doing. All was quiet downstairs, but Sirius didn't think it was because they were straining their ears. He moved quickly back to Regulus' door and pushed it open more so he could fit through the crack.

Regulus didn't hear Sirius enter; he was too busy stroking himself, legs spread and head back against the pillows. Sirius slowly and cautiously approached the bed. Regulus had sped quickened his pace, and Sirius could tell that he was close to finishing. Just as Regulus arched his back, relishing in his fantasy, Sirius had reached the edge of the bed and was not only close enough to take in every detail of his brother, but he was also close enough to touch him.

Sirius' breath caught in his throat. His next move would determine how this ended. He hesitated for a moment, doubt about hearing his name flitting across his brain, but he threw caution to the wind and climbed into bed with his brother.

Regulus' eyes flew open and he half shrieked, moving away from Sirius and making to cover himself. " _What in the bloody hell do you think you're doing?_ " Regulus hissed, his face turning a dark shade of scarlet.

Sirius decided to play it cool. He threw a grin on his face that he hoped didn't seem too nervous. "I heard you moaning my name."

Though no one would have thought it possible, Regulus' face grew to be a darker shade of red. "No you didn't…" he said, fidgeting with the bed sheets.

Sirius grew more confident. "Actually, I'm pretty sure you did." He moved so that he was hovering over his brother, pressing his thigh against Regulus' still half hard member.

Regulus bit his lip. "I…"

"Was just curious…?" Sirius supplied for him, slowing rubbing himself against Regulus' leg.

Regulus' breath hitched, still not entirely sure his brother wasn't just messing with him, "Y-yes…?" It sounded like a question.

"Do you want to find out?" Sirius grinned wider, leaning down to place a few tentative kisses against Regulus' neck.

"I…" Regulus closed his eyes as Sirius selected a spot near his collarbone and started to suck. He hesitated for a moment more before finishing with, "want you…"

Sirius took this as an open invitation to do whatever he wanted. He slid one of his hands under Regulus' shirt, tracing the fine lines of his stomach and chest. This was nothing like what he had done with anyone else, and he was well aware that if his parents knew what they were doing, he would probably be hexed into oblivion. Sure, pureblood families were incestuous, but the closest links in relations were first cousins, not brothers. Somehow, the thrill of defying his parents, even if they were unaware of his deviance, made it all the better.

Sirius' mouth made its way back up his brother's neck and found his mouth as his fingers found his brother's nipple. Regulus squirmed a bit underneath him, and, realizing that this wasn't a nasty prank, wrapped his arms around Sirius, pulling him closer. The fingers of Regulus' left hand found Sirius' hair and wound themselves into his long tresses. Sirius made a hum of approval and Regulus parted his lips, welcoming his brother's exploring tongue.

Sirius' hands wandered down to Regulus' thighs, pushing his trousers down further. Regulus was all too happy to be free of them, pressing himself up against his brother, wanting to feel him. Sirius sucked on Regulus' wandering tongue, hand moving back up to wrap around his cock. Regulus moaned, hips bucking. Sirius chuckled and rubbed his thumb over the moist head.

The younger Black clawed at the back of his older brother's shirt, suddenly cursing the complexity of the clothes their parents made them wear. Frustrated, he pulled back and started unbuttoning Sirius' shirt to expose his smooth chest. Subconsciously, he licked his lips.

Sirius shrugged out of his shirt and threw it onto the floor. Regulus made to get out of his shirt too, but Sirius stopped him. "Leave it on," he insisted. The younger Black readily complied, and made to undo his older brother's trousers.

Sirius chuckled, "Eager now, are we?"

Regulus flushed and scowled. "No…"

Sirius smirked, "Liar."

Sirius deftly maneuvered out of his trousers tossed them to the side, adding to the pile of clothes on the floor. He moved down his brother's torso, his tongue leaving a wet trail in its wake. When Sirius had reached Regulus' member, he stopped and looked up at his panting and disheveled brother. Making sure he maintained eye contact, he took the tip into his mouth and smirked in approval at the needy sound Regulus made. Sirius licked at it teasingly before pulling back to cast a lubrication charm on his fingers. Shifting his position a bit, he took Regulus back into his mouth, flattening his tongue against the shaft as he gently pushed one finger into his brother's entrance.

Regulus gasped and squirmed a bit at the unfamiliar sensation, but he quickly forgot his discomfort as Sirius took more of his member into his mouth. While Sirius had Regulus distracted, he added a second finger and began scissoring them. He pulled back a little bit before taking Regulus all the way into his mouth, hollowing out his cheeks and closing his throat. Regulus groaned, lifting his hips off of the bed.

Sirius thrust in a third finger, and Regulus fisted his hands in the sheets, trying to thrust his hips. Gagging a bit, Sirius relinquished Regulus' member, licking the tip teasingly as he continued to thrust his fingers into his brother. Regulus made a needy noise as Sirius removed his fingers. Slowly, Sirius thrust into Regulus and leaned down to kiss his brother while he squirmed and adjusted to the intrusion. While sucking on Regulus' lower lip, Sirius started moving. Regulus inhaled sharply at the sensation, closing his eyes and focusing on his fantasy become reality.

"You like that hm, Reg?" Sirius asked, smirking as he nipped along Regulus' jaw.

"Nn…" was the only response he could manage.

Sirius chuckled and continued to thrust, eventually setting a steady pace, increasing tempo as he found his rhythm. Finding a spot on Regulus' neck to suck on, Sirius thrust slower and deeper, determined to find that one spot that would have Regulus seeing stars.

The younger Black pressed his hips needily up into Sirius' each time he pulled out, longing to feel friction against his swollen length. He entangled his hands in Sirius' sweat-damp locks, pulling Sirius back in for a kiss and slipping his tongue into his older brother's mouth, beginning to plunder it heatedly. Sirius moaned, and increased the intensity of his search, sliding his hands down to adjust Regulus' hips to get a better angle.

"Sirius…" Regulus groaned as Sirius finally found his prostate, eyes half closed with lust.

He thrust harder, slamming into Regulus' prostate with confidence this time. When Regulus moaned his name again, he slid his hand down to grip the his younger brother's throbbing erection. Sirius stroked up and down the hard length, leaning in to capture Regulus' lips and stop him from making noises loud enough to attract their parents' attention.

"Sirius…!" Regulus' cry was muffled against his brother's lips as he climaxed, nails digging into Sirius' shoulders.

"Regulus…" Sirius groaned as the already tight channel tightened even more around him and he came inside of his brother. He collapsed on top of Regulus, exhausted, but ears alert for any sounds coming from downstairs.

Nobody in the house was moving; all he could hear were his brother's and his own uneven breaths. He pulled out of his brother and got up, quickly gathering his clothes and putting them back on. Regulus made a noise of protest.

"What?" Sirius asked.

"You're just going to leave me like that?" Regulus asked, slightly affronted. He wanted a few questions answered.

"You really want mother and fathering coming up here and figuring out what just happened?" Sirius asked as he buttoned his shirt.

"Well… no…"

"Then I'll come back later, and we can talk then." Sirius said, straightening his shirt and moving towards the door.

"How much later?" Regulus asked, doubtful that they were going to talk about what had just happened.

"When everyone else is sleeping."

"Alright…" Regulus said as Sirius left the room. He lay back against his pillows and let out a slow sigh as he closed his eyes.

It had been even better than he had imagined it would be.

 _A/N: well, not only is this the first thing I've written in a very long time, this is also my first incest piece. I hope it was convincing enough… Also, is that ending too awkward? I wasn't really going to include their conversation in this little one shot, but the final line doesn't really seem like it has finality to it? Maybe it does and I'm just going crazy with sleep deprivation because it's 3:30 in the morning haha. This hasn't been beta'd, but I'll update it in a couple days when it's been more thoroughly proofread. Hope you enjoyed! :)_


End file.
